The rivets I provide with buckles and mounts have
been annealed and are very soft. Only a few tools are needed to add
your buckle or mount to leather. The basics are:
Awl
Some sort of peining hammer: ball, straight, or cross.
Snips.
Anvil-any block of hard metal will do.
Secret Tool

The Secret Tool is a nail set, which can be purchased at any hardware
store. The middle of a set of three is usually the best.

Poke a hole in your leather with your awl. For mounts, put the rivet
though the leather from the back. This will give you a metal backing to
rivet against. If you are attaching a buckle plate, you can rivet from
either side. Place the leather and rivet on the anvil, and slide the
mount onto the rivet.

Clip the rivet so that one to one and a half rivet
diameters protrude. Wear protective eyewear or close your eyes and look
away- the clipped off bit of rivet will fly in a random direction.

Hold the mount against the leather using open ships or pliers, and pein.

Once you have delivered a few hammer blows, the
mount should be locked to the leather. The pliers can be withdrawn and
the rivet hammered down causing the head to spread.

Don't hammer too hard, or for too long (practice
will let you know when to stop). Unless you have hammered quite a few
rivets, the rivet head won't be perfect. It will be rough and a bit
irregular. Now for the Secret Tool:

One or two strikes will round and smooth the rivet head.

If you are making a complete belt, start with the
buckle and strapend. I don't recommend using any measuring tools more
complicated than a finger. Mark two spots, each a thumb-joint
distance (or whatever your preference is) from the strapend or
buckleplate edge. Add mounts to these spots.
Fold the belt in half, mark the half-way spot, and
add a mount. Repeat until the belt is finished. Medieval spacing is
somewhere between touching and every four or five inches.